1. Field of the Invention
The present invention relates to a control apparatus of an internal combustion engine, and more particularly to fuel injection control at the time of transition from a stratified charge combustion operation to a homogeneous combustion operation in an internal combustion engine provided with first fuel injection means (in-cylinder injector) for injecting fuel into a cylinder and second fuel injection means (intake manifold injector) for injecting fuel into an intake manifold.
2. Description of the Background Art
In an engine having a main fuel injection valve (in-cylinder injector) injecting fuel directly into a combustion chamber of the engine and an auxiliary fuel injection valve (intake manifold injector) injecting fuel into an intake port, fuel injection control switching between an operation in a stratified charge combustion region (hereinafter, also referred to as “stratified charge combustion operation”) and an operation in a homogeneous combustion region (hereinafter, also referred to as “homogeneous combustion operation”) in accordance with an operation state has been proposed.
Particularly, in a fuel injection control apparatus of an engine disclosed in Japanese Patent Laying-Open No. 2001-020837, a fuel injection ratio of the auxiliary fuel injection valve (intake manifold injector) with respect to a total fuel injection quantity is set to 0 in the stratified charge combustion operation so as to carry out fuel injection only by the main fuel injection valve (in-cylinder injector). This can reduce the capacity of the main fuel injection valve, and the injection speed in the low-load region and hence performance of the stratified charge combustion is improved. In the homogeneous combustion operation, fuel injection is carried out at an appropriate fuel injection ratio between the main fuel injection valve and the auxiliary fuel injection valve, so that performance of the homogeneous combustion in accordance with the operation state can be obtained.